DESIGN AND FABRICATION OF HIGH-EFFICIENCY BEAM-SPLITTERS AND BEAM DEFLECTORS FOR INTEGRATED PLANAR MICROOPTIC SYSTEMS

High-frequency gratings with rectangular-groove profiles are used to g enerate high-efficiency beam splitters and beam deflectors. The effect s of the grating design parameters, i.e., period, groove depth, duty c ycle, number of phase levels, and polarization state (TE and TM) of th e incoming signal, are considered. The case of the binary beam splitte r grating is analyzed by using rigorous electromagnetic grating analys is. Fabrication techniques are presented in which three different lith ographic techniques are considered (optical contact, deep-UV stepper r eduction, and electron-beam direct write). Experimental results of 97% efficiency for the beam splitter grating and up to 80% for the beam d eflector grating are reported.